Regulatory Matters - Schedule of Actual Capital Amounts and Ratios (Details) $ in Thousands	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Triumph Bancorp Inc
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets) Actual Amount	$ 727,171	$ 715,142
Total Capital (to Risk Weighted Assets) Actual Ratio	0.137	0.130
Total Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Amount	$ 424,625	$ 440,087
Total Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Ratio	0.080	0.080
Tier 1 Capital (to Risk Weighted Assets) Actual Amount	$ 587,326	$ 581,580
Tier 1 Capital (to Risk Weighted Assets) Actual Ratio	0.111	0.106
Tier 1 Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Amount	$ 317,474	$ 329,196
Tier 1 Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Ratio	0.060	0.060
Common Equity Tier 1 Capital (to Risk Weighted Assets) Actual Amount	$ 501,859	$ 496,508
Common Equity Tier 1 Capital (to Risk Weighted Assets) Actual Ratio	0.094	0.090
Common Equity Tier 1 Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Amount	$ 240,252	$ 248,254
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.045	0.045
Tier 1 Capital (to Average Assets) Actual Amount	$ 587,326	$ 581,580
Tier 1 Capital (to Average Assets) Actual Ratio	0.104	0.108
Tier 1 Capital (to Average Assets) Minimum for Capital Adequacy Purposes Amount	$ 225,895	$ 215,400
Tier 1 Capital (to Average Assets) Minimum for Capital Adequacy Purposes Ratio	0.040	0.040
TBK Bank SSB
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets) Actual Amount	$ 655,551	$ 653,359
Total Capital (to Risk Weighted Assets) Actual Ratio	0.125	0.121
Total Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Amount	$ 419,553	$ 431,973
Total Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Ratio	0.080	0.080
Total Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 524,441	$ 539,966
Total Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets) Actual Amount	$ 623,674	$ 608,737
Tier 1 Capital (to Risk Weighted Assets) Actual Ratio	0.119	0.113
Tier 1 Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Amount	$ 314,457	$ 323,223
Tier 1 Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Ratio	0.060	0.060
Tier 1 Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 419,277	$ 430,964
Tier 1 Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	0.080	0.080
Common Equity Tier 1 Capital (to Risk Weighted Assets) Actual Amount	$ 623,674	$ 608,737
Common Equity Tier 1 Capital (to Risk Weighted Assets) Actual Ratio	0.119	0.113
Common Equity Tier 1 Capital (to Risk Weighted Assets) Minimum for Capital Adequacy Purposes Amount	$ 235,843	$ 242,417
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.045	0.045
Common Equity Tier 1 Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 340,662	$ 350,158
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Well Capitalized, Minimum	0.065	0.065
Tier 1 Capital (to Average Assets) Actual Amount	$ 623,674	$ 608,737
Tier 1 Capital (to Average Assets) Actual Ratio	0.111	0.113
Tier 1 Capital (to Average Assets) Minimum for Capital Adequacy Purposes Amount	$ 224,747	$ 215,482
Tier 1 Capital (to Average Assets) Minimum for Capital Adequacy Purposes Ratio	0.040	0.040
Tier 1 Capital (to Average Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 280,934	$ 269,353
Tier 1 Capital (to Average Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	0.050	0.050